There are 5 main classes/skill sets in Contract Wars: Scout, Assault, Destroyer, Sniper and Gunsmith. The careerist skill set is primarily used to boost the player's progress and grant other skills.

Your class will be specified by the class that spent the most amount of SP in. For example, if you spend the most SP into Scout skills, you will be a Scout. Thus, when joining a clan, you will be assigned to the benefit of Scout Clan skills and not other Clan skills for other classes. When using the clan skills, the make sure that your skill points are more suited in that skill set. e.g. a player who spent 50 skill points on the Scout class will not be able to use the clan's Assault skills, where s/he spent only 10 skill points.

At the end of this article will also discuss some of the significant class-specific skills and strategies that go with them, which will have considerable effect on the performance of the player. Some of the important notes will also be included. The skills that are about to be discussed will not have an effect on their weapons' statistics (eg. damage, recoil, ...) nor unlock the special weapons (eg. Vityaz SMG, PKP Pecheneg, ...), but rather the change in playing experience the player will receive for unlocking them. For this purpose, Careerist skills will not be included in the discussion.

Assault

The Assault tree mainly focuses on primary weapon damage, and depending on the player's build, may grant armor skills and health regeneration. Players should focus on this skill set if they want balanced, fun game play.

Special Bullet Shape will provides +5 penetration to main weapon and +3 penetration to secondary weapon instead of only +5 penetration to main weapon only as described in CWClient

FMJ Ammunition only provides +3 damage instead of +5 as described in CWClient

Soft-Point Ammunition only provides an extra +7 damage instead of +10 as described in CWClient

Destroyer

The Destroyer tree mainly focuses on recoil, and depending on the player's build, may grant access to the EFD grenade(s), more ammo, or the powerful Fire Stabilization skill. Players should focus on this skill set if they want to bear the brunt of the damage. Many of the skills here benefit heavy weapons with <45 mobility.

Pneumatic Stock only provides -2 recoil instead of -7 recoil as described in CWClient

Recoil Physical Damping only provides an extra -8 recoil instead of -15 recoil as described in CWClient

Sniper

The Sniper tree mainly focuses on accuracy of the primary weapon, as well as giving more awareness of the environment around him. Players should focus on this skill set if they want to keep away from the brunt of the battle, supporting their team from afar by picking off enemies.

Alfa Group Sharpshooting Course only provides an extra +5 accuracy instead of +7 accuracy as described in CWClient

K-43 Sniper Training Course only provides an extra +8 accuracy instead of +15 accuracy as described in CWClient

Gunsmith

The Gunsmith tree mainly focuses on enhancing weapon mod stats and boosting the effectiveness of the sonar and mortar support items. This skill set is seldom used because of the fact that its skills are the least influential in battle, though he can be a power that needs to be reckoned with if s/he has the right skills and weapons. The class also provides cheaper repair costs. Players should focus on this skill set if they want to conserve their CR, use highly modified weapons, play mainly TacticalConquest and TargetDesignation or want to support their team more effectively.

The class specific weapon that needs to be unlocked by a skill is the IWI UZI PRO SMG.

Mortar Expert I provides 8 shells per strike instead of 5 as described in CWClient

Mortar Expert II provides 15 shells per strike instead of 8 as described in CWClient

Sonar Expert I increases sonar radius by x1.5 times instead of x2 as described in CWClient

Sonar Expert III increases sonar radius by an extra 15 metres instead of 30 metres as described in CWClient

Optics Ranging provides an accuracy bonus of +3 to optics instead of +5 as described in CWClient

Composite Materials Of Silencers provides an accuracy bonus of +3 to silencers instead of +5 as described in CWClient

Silencer Parts Alignment reduce damage-loss caused by silencers by 75% on customisable weapons and by 100% on uncustomisable weapons, instead of completely negating damage-loss of all weapons as described in CWClient

Careerist

Unlike the other skill trees, this skill tree was made exclusively for renting. Skills here lasts as long as the player chooses, and the available renting times are the same as weapon renting times, being 1 day, 5 days, or 30 days. The only exception to this rule is the Profile View Blocking skill, which only provides of either 5 days or 15 days of use.

Most skills here are boosters that either increase the exp and CR gain per round. Other skills can boost the progress of W-Tasks, Contracts, and Achievements. Unlike the other skill trees, there are no "prerequisites" needed to rent each skill, meaning you do not need to have a certain skill needed to unlock a careerist skill.

Significant Skills, Strategies In Skill Investments And Employment

Please note, this discussion will talk about the unique skills of significance and is NOT a guideline of what essential skills to get, since most players will most probably do not have the SP to unlock every of these skills. Be rational and choose what is needed the most. More guidelines about essential skill choosing and the reasoning behind them can be found on various threads of Kongregate Contract Wars forum.

Scout:

Scout Operator: The Scout Operator skill allows for fast weapon switch, which is a very good complement skill for players who tends to rush at high pace in close quarters and small maps and have to reload or change gun for emergency situation a lot. More importantly, this skill will mitigate the reduced the changing time of some particularly slow-to-change weapon, including the EBR Marksman rifle and machine guns such as the RPD.

Analyst II: As the name suggests, this skill will display the health of the enemy when they are hit by the players' weapons for a short amount of time. This has an added benefit of showing the position and movement of the opponent who take cover behind many objects, no matter how far they are away. This is a highly beneficial trait especially for mid-to-long range combat or combat in close quarter behind soft covers. Many of the covers in Contract Wars can be shot through depend on the penetration power of the weapon, and covers like wood and thin metal sheets can be shot through by almost any weapon, dealing an amount of damage to whoever hiding behind them. Use the positional revelation capability of Analyst II to evaluate if the cover behind a recently-shot enemy can be shoot through to finish him off, or to check if there is anyone hiding behind certain covers.

Shadow Training: Shadow Training allow for silent movement in all condition, whether it be in the bushes, on concrete or inside aluminium containers. While expensive, this is a powerful skill, especially in deathmatch and small maps. The ability to move completely undetected while listening to the footstep of other players allows for easy flanking of unsuspecting enemy camping a certain position, ambusing opponents in small maps (eg. bay5) or infiltrating enemy team from behind.

Assault:

Armor is a big part of the Assault skill tree, as its protection against damage is of undeniable usefulness. In some cases, players with less health than the damage of the bullet will be able to survive a few extra shot even with almost depleted armor value, as part of the damage is deducted before being counted as an actual hit. While the amount of armor will vary depending on what level of armor is invested into, and whether if the clan is renting a Clan Armor skill, the amount of armor will offer significant difference in protection not of the armor value, but what part of the body they will protect in line with the complex hitbox system of the model in Contract Wars. The protection level is as follow:

20 and 40 armor points in total including clan armor will protect the upper abdomen ONLY.

60 armor points in total will protect both the upper and lower abdomen.

100 armor points and above in total will protect both abdomens and also the upper limbs (2 arms).

Exceptions for this includes the Fort Rosich + Helmet Assault skill which will be able to protect against a single headshot with damage lower than 60, Armor Plates For Limbs Scout skills which reduces damage on both upper and lower limbs at a solid 20% rate (all arms and legs), and Musculature Heavy skill which does not affect the regional protection above. The first two are rentable skills.

From this, it is deducted that only 20 armor points and 60 or above armor points are worth investing on. So if a player already have 20 points protection from clan armor, has limited SP and is questioning whether the SP is to be spent on the first-level SYS armor or on something else, it would be advisable to not buy the SYS armor, since 20 armor points is more cost-effective than 40 armor points.

However, if this person has access to the first two Clan Destroyer skills as a Destroyer, he will already have 40 armors in total. And thus, buying the Kevlar armor will bump the total armor point to 60 points, which will offer another different level of protection to the player. However, if his clan is renting armor then he will have 60 armors in total, which makes buying new armor unpractical. Also, if a player is not in a clan or his clan is not renting armor, and he has enough SP to proceed directly to Defender-2 armor, it would be advisable to buy this skill for the same reason as above.

Heavy:

Note: Killing Element is a Heavy grenade skill that can be purchased from a Package in Weapon Set 4, but the package has been removed from the game since CWClient update and can no longer be purchased without proceeding down the grenade branch of the tree.

Fire Stabilisation: Fire Stabilisation helps decrease the cone-of-fire (the wideness of the crosshair) after a certain amount of bullet has been fired back into its original state before firing while the weapon is still continuously being fired. To make the most out of this skill, either uses a high firerate or high recoil weapon where the Fire Stabilisation will take effect faster, or a high capacity weapon where there are a lot of bullets available for sustained fire. This skill is particularly useful for players who operate with machine guns to commence highly accurate suppression fire on the positions of the enemy.

Stopping Bullet: This is a powerful yet underused skill, highly usable especially for weapons with lower accuracy or damage. Although only players with good internet connection would be able to make the most of this skill, Stopping Bullet will almost guarantees a win during 1-versus-1 situation in short to mid range, giving the enemy extremely low chance of retaliating due to the reduced accuracy on their side.

Sniper:

Note: Fluorescent Mark used to provide weapons with a glowing mark on the iron sights for easier aiming in low light conditions. However, an update has provided all of the weapons with a glowing mark, thus making this skill practically useless and a waste of SP.

Armor Detection: While giving the ability to detection enemy's usage of armor, it also provides a brief tactical positional advantage in a short period of time similar to Scout's Analyst II. Refer to the Scout section for how to take advantage of this feature.

The Professional: This skill allows the first shot of the first bullet in the magazine of any primary weapon to be 100% pinpoint accurate, and by reloading the weapon this skill become usable again. This skill opens up endless unique possibilities, allowing weapons that traditionally can kill with one headshot at any range but have low accuracy like H&K MP7, many SMGs and assault rifles to push the boundary and participate in long range combat with exceptional effectiveness. Highly viable skill for players who are more familiar with close range combat, but still want to retain a major degree of effectiveness in longer-ranged combat.

Guaranteed Detection: This skill pinpoints the exact location of an enemy once that enemy is somehow detected on the minimap either by firing their unsilenced weapons or being sonar-scanned, and the revelation will remain until the enemy's detection signal disappear from the minimap. Guaranteed Detection is not affected by how far an enemy is away from you, and will always work as long as he is detected on the minimap. Using this information, the player can retaliate immediately to target who opened fire at them camoflaging without hard cover, or evaluate whether the cover where the enemy is hiding behind can be shoot through with their weapon. A combination of Guaranteed Detection, Advanced Hearing (detects silenced shots) and Analyst II or Armor Detection is an extremely powerful surveillance combo, which can even sometimes be nicknamed "legitimate wallhack".

Gunsmith

Note: Repairer IV and Master Repairer had been disabled due to the sheer advantage they can provide for some CR weapon users, including the ability to unbreak certain powerful but expensive to maintain weapons, for example the old M4A1 and AUG, at a cheap price.

Silencer Parts Alignment: This skill has different effects on certain types of weapons. For weapon with a damage-reducing W-Task due to silencer but has no customization (eg. DT-MDR, TT pistol, M40A6,...), the damage reduction is completely negated if this skill is obtained. However, for weapons with customization and can equip silencers, the skill only reduces 75% of the damage-loss caused by the silencer. This skill also works on sidearms, however it has no effect on weapons with integrated or pre-installed silencers, such as the AS VAL weapon series, VSS Vintorez, SRS mk.2 or SVU-AS.

Trivia

A fan-made site was made for calculating skill trees as well as viewing weapons stats, created by a collaboration of Kongregate user serdeila and other players. However, this site is now outdated and should be used as a reference only.

In careerist skill tree, there used to be a skill called "Skill specialist," which gave the players double the amount of SP earned every 5 levels. However, it was removed due to an exploit that gave new players an unfair amount of SP.